Pigeon headaches revealed.

When pigeons eat birdseed off the sidewalk, do they bang their beaks on the concrete?

-- Mission Valley Ken

Peck. Ouch! Peck. Ouch! That's kinda how a pigeon's day goes. Well, not that bad, really. The keratin sheath that coats its bill (which in turn protects its internal beak bone) is hard at the tip but softer near the skull, absorbing some of the shock. On all ground feeders, the keratin grows continuously, so the bill doesn't wear away.